Aquasphere earplugs are designed to prevent pressure from being built up inside the ear thus increasing comfort. Constructed with high-quality silicone to increase the life as well as the comfort in the outer ear. Comes with a portable case so it's handy to carry.
Aquasphere X4 earplugs are avoiding pressure inside the ear when you are diving and it increases the comfort level. Built with top-level silicone to expand the lifetime of the earbuds. The silicone will give more comfort to the ear. The buds come with a cover, so after use can hold it safely.